Over the past few months, several of my friends have come and asked me to explain HOV (High Occupancy Vehicle) lanes, commonly referred to as carpool lanes and their tolled cousins, HOT (T=Toll) lanes. They ask me to explain them because in their view, they don’t do anything except take away a lane of traffic from everyone else, discriminate, or double tax the user. Additionally, they contend that HOV/HOT lanes aren’t that much better at reducing congestion because they usually see them moving at a similar speed as normal lanes. They don’t understand why planners want to impose more of these lanes on freeways. To answer this isn’t simple. It requires the average person to conceptualize a complicated system of interplaying transactions to show how HOV and HOT lanes actually work. I will, nonetheless, give it a shot. First, I will explain the way HOV and HOT lanes work, then I will go over the HOV, HOT lane experience in Los Angeles County and then address the two concerns of critics: double taxation and inequitable taxation.